Action: Irrigate peatland (before/after planting)
Key messagesRead our guidance on Key messages before continuing
- One study evaluated the effects, on peatland vegetation, of irrigating areas planted with peatland plants. The study was in a bog.
- Cover (1 study): One replicated, paired, controlled, before-and-after study in a bog in Canada found that irrigation increased the number of Sphagnum moss shoots present 1–2 growing seasons after sowing Sphagnum fragments.
Irrigation systems, such as sprinklers, could be used to maintain a damp peat surface and stop planted vegetation from drying out (Rochefort & Bastien 1998). Water could be recirculated from drainage ditches or ponds on the peatland. Irrigation can be expensive so may be best used as a short-term intervention to kick-start restoration.
Caution: A suitable water source, with the right level of nutrients and acidity/alkalinity, must be chosen to avoid altering chemical conditions on the peatland (Lamers et al. 2002). For example, bogs should only be irrigated with water stored on the bog, not ground water. Taking water for irrigation might reduce water levels in neighbouring wetlands.
Key peatland types where this action may be appropriate: bogs, fens/fen meadows, tropical peat swamps.
Related action: irrigate peatlands without introducing vegetation.
Lamers L.P., Smolders A.J.P. & Roelofs J.G.M. (2002) The restoration of fens in the Netherlands. Hydrobiologia, 478, 107–130.
Rochefort L. & Bastien D.F. (1998) Réintroduction de sphaignes dans une tourbière exploitée: évaluation de divers moyens de protection contre la dessiccation (Reintroduction of Sphagnum to an exploited bog: evaluation of various methods for protection against desiccation; in French). Écoscience, 5, 117–127.
Supporting evidence from individual studies
A replicated, paired, controlled, before-and-after study in 1993–1994 in a historically mined bog in Quebec, Canada (Rochefort & Bastien 1998) found that irrigating plots sown with Sphagnum-dominated vegetation fragments increased the number of Sphagnum moss shoots present. The effect was biggest after one growing season (irrigated: 250–630 shoots/m2; not irrigated: 60–310 shoots/m2) but persisted after two growing seasons (irrigated: 95–770 shoots/m2; not irrigated: 50–390 shoots/m2). Irrigation also increased the number of Sphagnum shoots in additional plots that were not sown (see intervention Irrigate peatland). In spring 1993, three pairs of plots were established on slightly drained, bare peat. Sections of each plot were sown with vegetation fragments, dominated by one of three Sphagnum moss species (250 fragments/m2). Three plots (one plot/pair) were irrigated during the summer, using sprinklers and water stored on the bog. The other plots were not irrigated. In autumn 1993 and 1994, all Sphagnum shoots were counted in forty 30 x 30 cm quadrats/plot.